Explain the concept of buoyancy to your kid with this DIY experiment 

Do you have a budding young scientist at home? Or is there a young learner who’s always up and about to know how things work around the house? Well, as parents, you can nurture their curiosity through easy-peasy science experiments from the comfort of your home. Do-It-Yourself (DIY) science activities make learning enjoyable and help kids grasp complex concepts in a relatively easy way.  

Buoyancy is a science concept that many students find difficult to understand. When an object is fully or partially immersed in a fluid, the fluid exerts an upward force. This is known as buoyancy, a concept explained by Greek scientist and mathematician, Archimedes. The Archimedes Principle states, “The upward buoyant force that is exerted on a body immersed in a fluid, whether partially or fully submerged, is equal to the weight of the fluid that the body displaces and acts in the upward direction at the centre of mass of the displaced fluid.” 

Here is an easy DIY experiment to explain the concept to kids.  

The experiment 

This a water and orange experiment to explain to your kids why things float or sink when outside force is applied to them. 

What you’ll need   

• A tall glass 
• Water 
• Any citrus fruit, such as oranges 

• A rock, twigs or seashells 

How-to   

Get these ingredients on a table, call your child, and start the experiment. Here’s a step-by-step guide. Encourage your kids to follow these.  

• Fill the glass with water. 

• Add an orange to the glass. 
• Observe what happens to the orange. 
• The orange floats on top of the water. 
• Try pushing the orange to the bottom of the glass with your hand. 
• It still keeps on floating on top of the water. 

• Now, peel the orange and keep the peel aside. 
• Put the orange in the glass of water again. 
• The orange sinks and settles at the bottom of the glass. 
• Similarly, you can try dropping rocks, twigs and seashells in the water. 
• Observe which of them floats or sinks. 

• Twigs will float while seashells and rocks will sink. 

Why did the unpeeled orange float while the peeled one sank? 

The density of an object and the fluid in which it is immersed determines whether it sinks or floats. An object with a higher density than the fluid will sink, while a less dense object will float. Thus, an unpeeled orange and twigs continued to float whereas the orange sank after removing its peel. In other words, the orange peel was full of air bubbles. Since the bubbles were less dense than water, they kept floating while the density of oranges without peel was more than that of water. Hence, they settled at the bottom of the tumbler. Hence proved, that a buoyant object is one that floats.